PM Generators Ltd.

MPPT: Maximum Power Point Tracking 

Maximizing Power output of wind permanent magnet generators with MPPT

Maximum Power Point Tracking or MPPT is an electronic system that allows grid tie inverters and battery chargers to get maximum power from the electricity source. These sources can be solar panels or other renewable sources like wind using permanent magnet alternators. MPPT is a technique through which maximum power is obtained. For wind generators, a controller compares the output of the pm alternator and compares it with the battery voltage. MPPT changes the electrical output voltage and current levels. This available power is provided to the battery in the form of increased current. MPPT detects the optimal power that can be obtained from the system and thus makes changes in the voltage.

Example

Imagine a conventional controller (non MPPT) that connects the alternator (75W) to the battery (12V) to charge a discharged battery. This makes the permanent magnet alternator operate at the battery voltage which may not be the ideal voltage at which the module is capable of producing. The maximum power may be obtained at some other voltage point. By limiting the voltage to 12V, the 75W wind generator system is able to produce power limited to a 53W module. Hence potential is not reached.

With a MPPT system attached arrangement, the controller will detect the voltage at which the module gives its maximum possible voltage which in this example is of 17V. The MPPT system then operates the module at 17V and extracts complete 75W of power. This is irrespective of the current battery voltage.